wattle (bark)

A vegetable tanning material obtained from the
bark of the black wattle (Acacia mollissima),
indigenous to Australia but cultivated extensively
in South Africa and other areas. Large quantities
of wattle are exported, much of it to England, in
the form either of the bark itself, or as the
extract. The tannin content of the bark ranges
from 30 to 45%, with the average being about 35 to
39%. Wattle is essentially a tannin of the
condensed class; it has a high pH value, a low
salts and acids content, and a relatively low
viscosity, especially in warm solutions. It is
very astringent, penetrates the hide substance
rapidly, and has a high degree of tan fixation.
Like most other vegetable tannins, it is seldom
used alone, but generally in mixtures with
myrabolans, sumac, valonea, etc. Also known as
"mimosa." See also: VEGETABLE TANNINS .
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